The subject invention is directed toward the art of adhesive bonding and, more particularly, to an adhesively bonded flexible, laminated article and a method of making the same.
The invention is especially suited for manufacturing laminated sheet materials used in making shoe uppers and will be described with particular reference thereto; however, the invention is capable of broader application and could be used for making a variety of similar, flexible laminated products useful in many different environments.
Modern shoe fashions prescribe relatively frequent and sudden changes in the outer materials used in the manufacture of shoe upppers. The manufacturing methods and the materials used for shoe liners have, however, remained relatively constant.
A typical shoe liner material comprises a woven fabric, such a nylon tricot bonded to a thin layer of urethane foam or some other type of foam product. A layer of flannel or a non-woven stock is normally bonded to the other side of the foam.
In the process of making a shoe, the flannel face of the liner laminate is bonded to the shoe upper material in large sheets. The nylon tricot surface becomes the inner surface of the shoe when the laminated liner-upper material is cut into the necessary shapes and sewn into a shoe upper.
The prior methods used for bonding the liner laminate to the upper material have been an ongoing problem and have made it difficult to quickly change over to different shoe outer materials.
Typically, two different bonding methods have been used. The first relatively common method has been to use a liquid adhesive which is coated on the inner surface of the shoe outer material. The shoe liner material is then bonded to the adhesive coated surface using manual or machine lamination methods. As can be appreciated, this method is both messy and time consuming.
The second method often employed is to use a shoe liner material which has been precoated with a pressure sensitive adhesive which is overlayed with a removable protective sheet or liner. Bonding between the liner and upper material takes place substantially instantly when the protective sheet is removed and the liner is applied to the upper material. This method has resulted in increased manufacturing efficiency but has two distinct drawbacks. First, the method causes the softness or "hand" of the liner to be adversely affected. Secondly, the continuous layer of pressure sensitive adhesive acts as a vapor barrier and makes the shoe liner non-breathable. As a result of these drawbacks, the use of this second method has been severely limited.
As can be appreciated from the foregoing, there is a distinct need for an improved method for bonding shoe liner materials to shoe upper materials.